Submarine sonar systems include a towed sonar array that is deployed behind a moving submarine. The sonar sensor part of the towed array may be more than 1000 yards behind the submarine. This enables the total sonar system to detect other vessels and through triangulation establish an accurate distance to the detected vessel.
When the towed array is retrieved into the submarine it passes through an outboard sensor assembly (OSA), usually in the vertical stabilizer of the submarine. The outboard sensor assembly contains electronic instrumentation necessary to monitor the passage of the towed array during deployment, towing, and retrieval and to relay that information to submarine personnel.
Due to the corrosive environment of the ocean the housing of outboard sensor assemblies have been machined from Monel, an alloy containing nickel, copper, iron and other alloys, with nickel being the primary component, followed by copper and then iron. The resulting outboard sensor assembly is relatively difficult to machine, expensive, and heavy. The weight is important because divers often do repair of an outboard sensor assembly underwater while the submarine is in port. The Monel housing surrounds an interior tube composed of either Monel or polymer through which the towed array passes. A common failure mode of this design is electrical shorting caused by seawater leaking into the interior of the Monel housing where electronic components are contained. These failures and the combination of the weight and costs of the system results in high operation and support costs of replacing failed units during submarine maintenance periods.
There is an unmet need then for a new outboard sensor assembly, one that is lower cost, easier to manufacture in quantity, lighter weight, less likely to leak, and with a lower failure rate. The instant invention to be described meets those needs.